1. Field of the Invention
The present invention relates to a method of forming a key-engaging part of an axial-hole member and a key-engaging part structure to be used in industrial devices, transport devices, and so on.
2. Description of the Related Art
Conventionally, it is well known in the art that there is a method for allowing a power transmission between a shaft and an axial-hole member. Such a conventional method comprises the steps of: forming a key way in the axial-hole member having the shaft and an axial hole in which the shaft can be.-fit; and engaging a key with the key way to make a connection between the shaft and the axial-hole member.
In the case of the axial hole being bored in the axial-hole member in the axial direction, the key way can be formed in the axial-hole member by inserting a cutting tool such as a broach from the one end of the axial hole to the other end thereof in the axial direction.
On the other hand, in the case of a non-penetrated axial hole having one closed end in the axial direction, a broach or the like cannot be inserted through the axial hole. In the prior art, therefore, a key way is formed in the axial-hole member using a slotter.
As shown in FIG. 14, the slotter is a machine tool for making a key way 204 by the steps of contacting a bite (i.e., a cutting tool) 202 with the inner peripheral side of an axial hole 200 and reciprocally moving the cutting tool 202 in the axial direction, while gradually moving the cutting tool 202 outward in the radial direction.
However, the key way processing using such a slotter requires to move the bite 202 back and forth many times in the axial direction in order to finish a key way 204, resulting in problems where the machining of key way is inefficient and a machining cost is high.